1. Field of the Invention
The present invention relates generally to two-piece electrical connectors for connecting two circuit boards and, more particularly, to a two-piece electrical connector having a large number of terminals.
2. Description of the Prior Art
The mounting density of circuit boards increases as the integration density of semiconductor devices increases. For example, the number of terminals of a conventional LSI package has been about 100, but now it is 400 or more. As a result, the number of terminals to be connected across circuit boards is increased to 200 or more.
Components are mounted on a circuit board with the aid of flux and solder. In order to avoid problems with the movement of fluxed contacts, the stand-off of a connector above the circuit board has been increased or a chemical treatment has been applied to terminals to prevent the flux from flowing along the terminals. However, since the terminals are press fitted into the housing, there can be spaces around the terminals so that the flux can flow along the terminal or the space and deposit on the terminal contact, causing poor contact. Especially, multipole connectors of the press fit type require washing upon soldering in order to prevent any problems with the shift of fluxed contacts, thus presenting an economical problem.
As for conventional connectors having up to about 100 terminals, it has been proposed to shield the circuit board and the terminal contacts so that no flux flows into them. However, they have only two rows of terminals and present little or no problem for integral molding by which all of the terminals are molded in the housing at once. There is demand for super multipole connecters which have three or more rows of terminals. Such super multipole connectors require a fitting guide and a device for preventing damage to the connector which arises from an oblique pulling out operation. However, so far there are no super multipole connectors on the market because of lack of the manufacturing technology.